Holonomic/Omni vs Defense

[Alex Burman]

I have been seeing allot of teams and talk about having holonomic or omni wheel drive. I'll be the first to admit I don't know everything about them or the differences between the 2, if any.
But I was wondering what everyones thoughts were on how a robot using a holonomic or omni wheel drive system would stand against being rammed by a defensive robot? If it were to be hit in the side as its trying to aim or shoot wouldn't it be more likely to be pushed/pushed easier and thrown off target?

[Koko Ed]

Originally Posted by Grayswandir-75

I have been seeing allot of teams and talk about having holonomic or omni wheel drive. I'll be the first to admit I don't know everything about them or the differences between the 2, if any.
But I was wondering what everyones thoughts were on how a robot using a holonomic or omni wheel drive system would stand against being rammed by a defensive robot? If it were to be hit in the side as its trying to aim or shoot wouldn't it be more likely to be pushed/pushed easier and thrown off target?

I figured Omni's would get pushed all over the place the same way robots with casters do.

Yeah, Holonomic's are never auite good at defense. However, with a good driver and some nice programming, you can avoid being pushed by dodging.

From a more technical perspective, It's actually quite clear why Holonomic's get pushed easily. Most of the time their rollers are made out of plastic, which when smooth isn't the best traction surface. Therefore a more gripping surface, like wedgetop, will have better traction.

[Andrew Blair]

Originally Posted by 114ManualLabor

Yeah, Holonomic's are never auite good at defense...

I'm quite convinced that this year, omni's will, to an extent, rule the defensive end of the game. The fact is, there appear to be many low shooting robots, and with an omni-drive "hovering" in front of an opposing shooter, they can, in effect, stop them completely.

As far as corner goal blocking goes, because there are only two defensive robots, defenders will need to perform double duty. A fast, manueverable robot (omni) will be able to quickly block shots, then run to a corner and get in the way of a corner goal dumper. You don't need to be able to push to defend the corner goal; you just need to sit in front of it. Anyone pushing you will only be digging themselves in deeper.

Now, as soon as a shooter has a 5' shooter, all bets are off. In my opinion, pushing ability is only useable (realistically) when *violently* offronting a shooting robot, or pinning an opponent to keep him from going to the corner goal. The better robots will be able to shoot even if you pin them.

[Cody Carey]

Omni wheel robots are going to be murdered this year...

Push an omniwheeled robot with a 4/6 wheel or tank driven robot, and they are going wherever you say... they can't help it. As Blair said, Omniwheel bots will be more agile, but if I have an omniwheel bot in front of me, all I'd have to do is push him out of the way. But... omniwheels will be much better suited to shooting on the fly and dodging regular defensive bots... I guess we'll have to see.

[Donut]

I expect omin drive robots to be very powerful offensive robots (manuverability plus the ability to shoot well is quite a combo). On defense they will work well for standing in front of an opponent, but against tall shooters (like ours will be), they're pretty powerless.

[kaszeta]

Originally Posted by Cody C

Omni wheel robots are going to be murdered this year...

Push an omniwheeled robot with a 4/6 wheel or tank driven robot, and they are going wherever you say... they can't help it.

Depends on how you do it. I'm pretty sure our omni will be able to handle this.

[Jared Russell]

By design, a standard holonomic drive (4 omniwheels at 45 degree angles or 4 mechanum wheels) only use about 70 percent of the available power for translation at any given time - simply because the rest is busy fighting the other wheels to stay straight. And that's not even taking into account traction differences.

We quickly ruled out omni-wheels this year because we determined that being unmovable was more important than being holonomic - and we can still spin on a dime. Defensively, yes, it is nice to be able to hover right in front of someone - but you can only be 5 ft tall, and many robots (ours at least) will be able to fire over that easily. Bumping and pushing seem to be the order of the day.

[dtengineering]

What if an omni-wheel equipped robot has a pneumatically activated platform that deploys to lift the wheels slightly off the ground.

Get in position, drop your platform, and you've got, say, two square feet of high-friction contact area.

Do your shooting, pick it up and go... while other robots drain their battery trying to move you.

Of course we're not using this strategy... but I'm sure with over 1,000 robots, that someone, somewhere is.

Jason

[Henry_Mareck]

you dont necesarily need to move them- if you push on a corner and spin them it has a good chance to throw off shooting, and unless they have a 360 degree shooter, then if you push them to the non-shoot region, they have to retract the brake, move, and lower it again.

[sgsdragons]

Our robot this year has the machanum wheels and it is actually fairly hard to push our robot around. I am the driver and I think that is someone is pushing me around, I will be able to counter the attack.

Just my 2cents

Josh
Team Driver/Designer

[DjAlamose]

Ok, being able to push robots around will help lots against shooters but it wont help a 1pt bot at all if there is a robot in front of the goal. There is nowhere to push that robot except into the goal, which would be at the fault of the defending robot not the pushing robot. If you plan to protect a corner goal then you had better be prepared to either go into the goal or have some way of preventing it.

I was always under the assumption that holmonic was 4 omnis in the corners and then 2 traction in the middle. With this you should have no problem pushing, its just spinning thats a problem. omni bots will probably do well this year as long as they can make them fast, i have seen a few omni bots that weren’t all that fast.

[sgsdragons]

i have seen a few omni bots that weren’t all that fast.

I will post a video of our machunam drive. IT's REALLY FAST!!!!!!!!! We have the wheels connected directly to the output shafts from our transmisions.

Josh
Team Driver/Designer

[EricH]

Originally Posted by DjAlamose

I was always under the assumption that holmonic was 4 omnis in the corners and then 2 traction in the middle. With this you should have no problem pushing, its just spinning thats a problem.

Nope, it's four in the corners at 90 degrees to each other. Normally, that is. Mechanum wheels could beat those pretty well (4 vs 2 isn't a contest normally). Most teams that use omnis use them 2 at one end and two high-traction wheels at the other.

[DjAlamose]

Originally Posted by EricH

Nope, it's four in the corners at 90 degrees to each other. Normally, that is. Mechanum wheels could beat those pretty well (4 vs 2 isn't a contest normally). Most teams that use omnis use them 2 at one end and two high-traction wheels at the other.

I knew what omni was but I didn’t know it was also called holmonic. But last year we had standard tank style drive with four wheels and they were all omni. We did this because our robot needed really good maneuverability and we could slide into place in front of the tetras. It was quite nice except when we were pushed from the side... o well. I can’t wait to see the video, I’m always interested in seeing other robots and how they work.